Irisin alleviates pressure overload-induced cardiac hypertrophy by inducing protective autophagy via mTOR-independent activation of the AMPK-ULK1 pathway

• Published in: Journal of molecular and cellular cardiology Vol. 121; pp. 242 - 255
• Main Authors: Li, Ru-Li, Wu, Si-Si, Wu, Yao, Wang, Xiao-Xiao, Chen, Hong-Ying, Xin, Juan-juan, Li, He, Lan, Jie, Xue, Kun-Yue, Li, Xue, Zhuo, Cai-Li, Cai, Yu-Yan, He, Jin-Han, Zhang, Heng-Yu, Tang, Chao-Shu, Wang, Wang, Jiang, Wei
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.08.2018
• Subjects: AMP-Activated Protein Kinases - antagonists & inhibitors; AMP-Activated Protein Kinases - genetics; AMPK; Angiotensin II - administration & dosage; Animals; Autophagy - genetics; Autophagy flux; Autophagy-Related Protein-1 Homolog - antagonists & inhibitors; Autophagy-Related Protein-1 Homolog - genetics; Benzamides - administration & dosage; Cardiac hypertrophy; Cardiomegaly - drug therapy; Cardiomegaly - genetics; Cardiomegaly - pathology; Fibronectins - genetics; Heart Failure - drug therapy; Heart Failure - genetics; Heart Failure - pathology; Humans; Irisin; Mice; Mice, Transgenic; Myocytes, Cardiac - drug effects; Phenylephrine - administration & dosage; Pressure; Pyrimidines - administration & dosage; Signal Transduction; TOR Serine-Threonine Kinases - genetics; Transverse aortic constriction; ULK1; Transverse aortic constriction; BNP; DMSO; JNK; LVP; LVIDd; LV; LVEDP; Irisin; Tg; EDV; mTOR; LC3B-I; LVEDV; RFP; EF; LVPWd; Cardiac hypertrophy; LVW/TL; FNDC5; FNDC4; AMPK; LVIDs; ULK1; Ang-II; LC3B-II; SQSTM1; ERK; dPmin; ANP; CK-MB; FS; LVESP; GFP; LDH; LVSd; WT; ATG5; dPmax; CC; SV; KO; CK; ESV; PGC-1α; CO; LVEDD; CQ; NRCMs; PE; Autophagy flux; TAC; 3-MA
• DOI: 10.1016/j.yjmcc.2018.07.250
• ISSN: 0022-2828; 1095-8584

In hypertrophic hearts, autophagic flux insufficiency is recognized as a key pathology leading to maladaptive cardiac remodeling and heart failure. This study aimed to illuminate the cardioprotective role and mechanisms of a new myokine and adipokine, irisin, in cardiac hypertrophy and remodeling. Adult male wild-type, mouse-FNDC5 (irisin-precursor)-knockout and FNDC5 transgenic mice received 4 weeks of transverse aortic constriction (TAC) alone or combined with intraperitoneal injection of chloroquine diphosphate (CQ). Endogenous FNDC5 ablation aggravated and exogenous FNDC5 overexpression attenuated the TAC-induced hypertrophic damage in the heart, which was comparable to the protection of irisin against cardiomyocyte hypertrophy induced by angiotensin II (Ang II) or phenylephrine (PE). Accumulated autophagosome and impaired autophagy flux occurred in the TAC-treated myocardium and Ang II- or PE-insulted cardiomyocytes. Irisin deficiency caused reduced autophagy and aggravated autophagy flux failure, whereas irisin overexpression or supplementation induced protective autophagy and improved autophagy flux, which were reversed by autophagy inhibitors Atg5 siRNA, 3-MA and CQ. Irisin boosted the activity of only AMPK but not Akt and MAPK family members in hypertrophic hearts and cultured cardiomyocytes and further activated ULK1 at Ser555 but not Ser757 and did not affect the mTOR-S6K axis. Blockage of AMPK and ULK1 with compund C and SBI-0206965, respectively, both abrogated irisin's protection against cardiomyocyte hypertrophic injury and reversed its induction of both autophagy and autophagy flux. Our results suggest that irisin protects against pressure overload-induced cardiac hypertrophy by inducing protective autophagy and autophagy flux via activating AMPK-ULK1 signaling. •Irisin is highly expressed in mouse hearts.•FNDC5 deletion aggravated and FNDC5 overexpression ameliorated the left ventricle hypertrophy, remodeling, injury and dysfunction induced by pressure overload.•Irisin supplementation attenuated hypertrophy in Ang II– or phenylephrine-induced cardiomyocytes.•Irisin alleviated cardiomyocyte hypertrophy in vivo and in vitro by inducing beneficial autophagy and autophagy influx via AMPK-ULK1 signaling but independent of mTOR.